Brushless motors, also known as electronically commutated motors, are electric motors that are powered by direct-current and have electronic commutation systems, rather than mechanical commutators and brushes. A brushless motor has permanent magnets which rotate and a fixed armature, eliminating the problems of connecting current to the moving armature. An electronic controller replaces the brush/commutator assembly of the brushed motor, which continually switches the phase to the windings to keep the motor turning. The controller performs similar timed power distribution by using a solid-state circuit rather than the brush/commutator system.
Brushless motors offer several advantages over brushed motors, including more torque per weight, more torque per watt, increased reliability, reduced noise, longer lifetime, elimination of ionizing sparks from the commutator, and overall reduction of electromagnetic interference. With no windings on the rotor, they are not subjected to centrifugal forces, and because the windings are supported by the housing, they can be cooled by conduction, requiring no airflow inside the motor for cooling. This in turn means that the motor can be entirely enclosed and protected from dirt or other foreign materials. However, brushless motors do require more complex and expensive control electronics than brushed motors. Brushless motors are typically controlled by a microprocessor to provide phase commutation, keeping the stator current in phase with the permanent magnets of the rotor. Without electronic commutation the brushless motor can not be properly controlled.
Brushless motors have been used in fuel pumps designed for a wide range of automotive applications. Brushless motors are growing in popularity but currently they have limited application in North America. They provide reliable, uninterrupted fuel flow at system pressure, high efficiencies, improved durability, wide-ranging harsh fuels compatibility, and reduced power consumption. Brushless fuel pumps are typically controlled by a micro-controller. In order for motor commutation to begin the micro-controller must complete its initialization routines. Extended initialization time can affect the ability of the motor/pump to achieve system level targets in the required timeframe. Failure of the microcontroller will immediately suspend the commutation functionality, preventing the brushless fuel pump from operating. Accordingly, it is desirable to provide a system and method for reliably controlling a brushless fuel pump.